Amine/hydrocarbon system

For ethylene glycol/hydrocarbon and amine/hydrocarbon systems, the calculahon should be checked for interface flow. The allowable interface flow for these two systems is 100 m /(m -day). 

Typical nonsieve, polar adsorbents are siUca gel and activated alumina. Kquilihrium data have been pubUshed on many systems (11—16,46,47). The order of affinity for various chemical species is saturated hydrocarbons < aromatic hydrocarbons = halogenated hydrocarbons < ethers = esters = ketones < amines = alcohols < carboxylic acids. In general, the selectivities are parallel to those obtained by the use of selective polar solvents in hydrocarbon systems, even the magnitudes are similar. Consequendy, the commercial use of these adsorbents must compete with solvent-extraction techniques. 

The physical solvent sulfolane provides the system with bulk removal capacity. Sulfolane is an excellent solvent of sulfur compounds such as H2S, COS, and CS2. Aromatic and heavy hydrocarbons and CO2 are soluble in sulfolane to a lesser degree. The relative amounts of DIPA and sulfolane are adjusted for each gas stream to custom fit each application. Sulfinol is usually used for streams with an H2S to CO2 ratio greater than 1 1 or where it is not necessary to remove the CO2 to the same levels as is required for H2S removal. The physical solvent allows much greater solution loadings of acid gas than for pure amine-based systems. Typically, a Sulfinol solution of 40% sulfolane, 40% DIPA and 20% water can remove 1.5 moles of acid gas per mole of Sulfinol solution. 

Hydrocarbon oxidation may also be considered a free radical chain-type reaction. At elevated temperatures, hydrocarbon free radicals (R) are formed which react with oxygen lo form peroxy radicals (R(X These, in turn, take up a hydrogen atom from the hydrocarbon to form a hydroperoxide (ROOH) and another hydrocarbon free radical. The cycle repeals itself with the addition of oxygen. The unstable hydroperoxides remaining are the major points for degradation and lead to rancidity and color development in oils, fats, and waxes decomposition and gum formation in gasolines sludging in lubricants and breakdown of plastics and rubber products. Antioxidants, such as amines and phenols, are often introduced into hydrocarbon systems in order lo prevent this free radical oxidation sequence. 

The above rules of thumb apply to organic and hydrocarbon systems, whose surface tensions are relatively low (a < 25 mN/m). For higher surface tensions, the liquid does not adhere well to the packing surfaces (underwetting), causing higher HETPs. In a water-rich system (a = 70 mN/m or so) HETPs obtained from Eqs. (14-156), (14-158), and (14-159) need to be doubled. For intermediate surface tension systems (some amines and glycols, whose surface tension at column conditions is 40 to 50 mN/m), HETPs obtained from Eqs. (14-156), (14-158), and (14-159) need to be multiplied by 1.5. 

AH corrosion inhibitors in use as of this writing are oil-soluble surfactants (qv) which consist of a hydrophobic hydrocarbon backbone and a hydrophilic functional group. Oil-soluble surfactant-type additives were first used in 1946 by the Sinclair Oil Co. (38). Most corrosion inhibitors are carboxyhc acids (qv), amines, or amine salts (39), depending on the types of water bottoms encountered in the whole distribution system. The wrong choice of inhibitors can lead to unwanted reactions. Eor instance, use of an acidic corrosion inhibitor when the water bottoms are caustic can result in the formation of insoluble salts that can plug filters in the distribution system or in customers vehicles. Because these additives form a strongly adsorbed impervious film at the metal Hquid interface, low Hquid concentrations are usually adequate. Concentrations typically range up to 5 ppm. In many situations, pipeline companies add their own corrosion inhibitors on top of that added by refiners. 

Trickle bed reaction of diol (12) using amine solvents (41) has been found effective for producing PDCHA, and heavy hydrocarbon codistiUation may be used to enhance diamine purification from contaminant monoamines (42). Continuous flow amination of the cycloaUphatic diol in a Hquid ammonia mixed feed gives >90% yields of cycloaUphatic diamine over reduced Co /Ni/Cu catalyst on phosphoric acid-treated alumina at 220°C with to yield a system pressure of 30 MPa (4350 psi) (43). 

Note Alarms and shutdowns as shown are not to be considered as meeting any minimum safety requirement but are shown as representative of types used for controi systems. Schematic Alarm/Shutdown Hydrocarbon Low Pressure Hot oil or Glycol Amine Label Description Line Heater Reboiler Steam Heater Salt Heater Reboiler Reboiler ... 

A typical amine system is shown in Figure 7-4. The sour gas enters the system through an inlet separator to remove any entrained water or hydrocarbon liquids. Then the gas enters the bottom of the amine absorber and flows counter-current to the amine solution. The absorber can be either a trayed or packed tower. Conventional packing is usually used for 20-in. or smaller diameter towers, and trays or structured packing for larger towers. An optional outlet separator may be included to recover entrained amines from the sweet gas. 

MEA systems foam rather easily resulting in excessive amine can y over from the absorber. Foaming can be caused by a number of foreign materials such as condensed hydrocarbons, degradation products, solids such as carbon or iron sulfide, excess corrosion inhibitor, valve grease, etc. Solids can be removed with cartridge filters. Hydrocarbon liquids aie usually removed in the flash tank. Degradation products are removed in a reclaimer as previously described. 

An amine absorber (Figure 1-15) removes the bulk of H2S from the sour gas. The sour gas leaving the sponge oil absorber usually flows into a separator that removes and liquefies hydrocarbon from vapors. The gas from the separator flows to the bottom of the HjS contactor where it contacts a countercurrent flow of the cooled lean amine from the regenerator. The treated fuel gas leaves the top of the HjS absorber, goes to a settler drum for the removal of entrained solvent, and then flows to the fuel system. 

The fourth chapter gives a comprehensive review about catalyzed hydroamina-tions of carbon carbon multiple bond systems from the beginning of this century to the state-of-the-art today. As was mentioned above, the direct - and whenever possible stereoselective - addition of amines to unsaturated hydrocarbons is one of the shortest routes to produce (chiral) amines. Provided that a catalyst of sufficient activity and stabihty can be found, this heterofunctionalization reaction could compete with classical substitution chemistry and is of high industrial interest. As the authors J. J. Bmnet and D. Neibecker show in their contribution, almost any transition metal salt has been subjected to this reaction and numerous reaction conditions were tested. However, although considerable progress has been made and enantios-electivites of 95% could be reached, all catalytic systems known to date suffer from low activity (TOP < 500 h ) or/and low stability. The most effective systems are represented by some iridium phosphine or cyclopentadienyl samarium complexes. 

Many volatile organic compounds (hydrocarbons, alcohols, aldehydes, acids, esters, ketones, amines, etc.) have been identified in marine systems [ 156,157]. These volatile materials may have an important role in the cycling of organic... 

Although the ECL phenomenon is associated with many compounds, only four major chemical systems have so far been used for analytical purposes [9, 10], i.e., (1) the ECL of polyaromatic hydrocarbons in aqueous and nonaqueous media (2) methods based on the luminol reaction in an alkaline solution where the luminol can be electrochemically produced in the presence of the other ingredients of the CL reaction (3) methods based on the ECL reactions of rutheni-um(II) tra(2,2 -bipyridinc) complex, which is used as an ECL label for other non-ECL compounds such as tertiary amines or for the quantitation of persulfates and oxalate (this is the most interesting type of chemical system of the four) and (4) systems based on analytical properties of cathodic luminescence at an oxide-coated aluminum electrode. 

Oxygenation rates were first examined for the system [Cu (R-XYL-H)]2+. In the model described here, two bis [2-(2-pyridyl)ethyl] amine (PY2) units are linked by a xylyl spacer group (R = H). Although initially proposed as a crude hemocyanin model, this system now is studied as a model for tyrosinase and is an example of hydrocarbon oxygenation taking place under mild conditions—that is, < 1 atm 02... 

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